Specifications

Model 900 Tool Guide
Page O17
Causes of increased fatigue stress in a demolition tool
A. Free running (or blank firing)
Free running occurs when the hammer piston strikes the top of the demolition tool when the work-
ing end is not in proper contact with the rock or concrete to be broken. This includes jobs where
the tool slides off the working area and also when breakthrough of thin concrete slabs or boulders
occurs.
B. Cold:
Low temperatures cause a demolition tool to be more susceptible to fatigue failure. Tools should be
warmed before use.
C. Mechanical and thermal damage:
Any form of damage to the surface of a demolition tool renders it more liable to suffer fatigue fail-
ure. Thus, all care must be exercised to prevent scratches, gouges or weld marks occurring due to
accidental damage, galling caused by contact between the tool and chuck bushing through the lack
of lubrication or excessive bending.
D. Lubrication:
Care must be taken to avoid metal-to-metal contact that, as a result of galling, could cause deep
damage marks which, in turn, may lead to the formation of fatigue cracks and eventually failure of
the demolition tool. Make sure that the shank of the demolition tool is well lubricated before insert-
ing it into the hammer.
E. Corrosion:
A rusty demolition tool is more likely to suffer fatigue failure. Keep tools well greased and sheltered
from the weather when not in use.
Typical failures
TRAMAC demolition tools are manufactured from first class materials and then heat treated to pro-
duce a fatigue and wear resistant tool. Thus, when the tool has apparently failed to give a satisfac-
tory service life, a brief visual inspection can often give a quick indication of the failure cause.
Wear is dictated by the conditions of the material being broken. In general, however, the following
guidelines apply:
Blank tools worn more than 1/3 of their diameter, or moils and chisels worn back more than
2 inches from the working end, are classed as reasonable life.